1. Field of the Invention
The present invention relates to an alternator having a vacuum pump capable of improving a cooling characteristic, and in particular to an alternator having a vacuum pump capable of improving a cooling characteristic which is capable of restraining a heat transfer to a bracket and brush of an alternator by effectively radiating a heat of a vacuum pump by providing a cooling unit which performs a heat sink function in a bracket installed in one side of a housing of a vacuum pump and capable of preventing a heat-degradation of oil supplied to the brush and into the vacuum pump in a vehicle vacuum pump which is installed in a portion of an alternator of a vehicle and which supports an operation of a brake, for thereby significantly enhancing a durability of the brush.
2. Description of the Background Art
Generally, in an alternator which is installed for a power supply of a vehicle, a vacuum pump is installed in a bracket of an alternator on the same axis of a rotary shaft of an alternator for thereby supporting an operation of a brake of a vehicle such as a diesel engine vehicle. The above vacuum pump is capable of sucking air into a housing, supplying oil, compressing the air using vanes. The compressed air is discharged through an outlet for thereby obtaining a certain vacuum. The thusly obtained vacuum is provided to the brake of a vehicle for thereby obtaining a certain braking force when a vehicle starts.
In the above conventional vacuum pump, a pump bracket is installed in surface-contact with a rear bracket of an alternator. A vacuum pump housing is installed in the pump bracket. The rotation rotor having vanes is installed in the interior of the housing. The rotation rotor is connected with a rotary shaft of the alternator on the same axis and operates together with the alternator when the engine starts for thereby generating a certain vacuum.
However, in the above conventional alternator, as the alternator operates, when the vacuum pump operates, a high temperature oil may be flown into the housing. As the rotation rotor of the vacuum pump operates, a high temperature heat occurs based on a friction between the vanes and the housing. The thusly generated high temperature heat may be transferred to the rear bracket and brush of the alternator through the pump bracket because there is not an effective heat radiating function in the system. Therefore, the bearings installed in the rear bracket and the pump bracket may be heat-degraded. As the brush of the alternator is heat-degraded, the durability of the bearings and brush may be significantly decreased.
In addition, the oil supplied to the vacuum pump may be over-heated by a continuing increase of heat, the vacuum pump may be critically heat-degraded. Therefore, the viscosity of the oil may be decreased for thereby decreasing the performance of the vacuum pump. In the case that the durability of the bearings is decreased, a certain gap may be formed between the bearings and the rotary shaft, so that oil may be leaked from the vacuum pump. Therefore, it is impossible to implement an efficient rotation of the rotary shaft, so that the performances of the vacuum pump and alternator are significantly decreased.
Accordingly, it is an object of the present invention to provide an alternator having a vacuum pump capable of improving a cooling characteristic which overcomes the problems encountered in the conventional art.
It is another object of the present invention to provide an alternator having a vacuum pump capable of improving a cooling characteristic which is capable of restraining a heat transfer to a bracket and brush of an alternator by effectively radiating a heat of a vacuum pump by providing a cooling unit which performs a heat sink function in a bracket installed in one side of a housing of a vacuum pump and capable of preventing a heat-degradation of oil supplied to the brush and into the vacuum pump in a vehicle vacuum pump which is installed in a portion of an alternator of a vehicle and which supports an operation of a brake, for thereby significantly enhancing a durability of the brush.
In order to achieve the above objects, there is provided an alternator having a vacuum pump capable of improving a cooling characteristic which includes a packing inserted in an outer circumferential portion of a center shaft hole of the pump bracket for implementing a sealing operation in surface-contact with the rear bracket, a certain space formed between the packing and the shaft hole for preventing a heat transfer, and a heat radiating unit installed in a lower surface of the pump bracket in the alternator in which a rotary shaft supported by bearings is installed in a rear bracket of an alternator, a housing of a vacuum pump having vanes and a rotation rotor is installed on the rotary shaft, and a pump bracket is assembled to a lower portion of the housing.